# PocketEngineer — RPN calculator & date math

> RPN calculator & date math (iPhone/iPad app by Ing. Markus Biermaier.)

- Source: https://appshunter.io/ios/app/pocketengineer/id6753213602 (this page in markdown: same URL + `.md`)
- Developer: [Ing. Markus Biermaier](https://appshunter.io/developer/1843098624)
- Category: Utilities, Productivity
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 4 MB
- Released: 2026-08-14
- Data updated: 2026-08-25
- User reviews in markdown: https://appshunter.io/ios/app/pocketengineer/id6753213602/reviews.md

## What is PocketEngineer?

A classic RPN calculator, handcrafted the old way.

PocketEngineer works like the legendary HP pocket calculators: a four-register stack (X, Y, Z, T), Enter instead of equals, and every keystroke exactly where your thumbs expect it. Built by an engineer who has used RPN for forty years — first in C++, now ported by hand to Swift.

WHAT MAKES IT DIFFERENT

• Date & duration arithmetic — subtract two dates and get days and hours, add 90 minutes to a timestamp, count the days until Christmas. Time math is a first-class citizen, not an afterthought.
• The Tape — a paper-tape history of every calculation. Tap any line to rewind the stack to that exact point. The tape never lies: even rewinds are logged.
• Real RPN — 4-register stack, Swap, Roll, Drop, stack always visible.
• Scientific board in landscape — trig, logs, powers, constants. Portrait stays a clean, plain calculator.
• 10 memory registers, persistent between launches.
• Hardware keyboard support on iPad.

HONEST SOFTWARE

Free forever. No ads, no tracking, no accounts, nothing locked. If you enjoy it, there is a small tip jar behind the info button — that's all.

Handcrafted by M. Biermaier.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Espresso | $0.99 | one-time |
| Cappuccino | $2.99 | one-time |
| Full Breakfast | $4.99 | one-time |



## Version history (last 1 release)

### 1.0 — 2026-08-14

No release notes.

## More apps by Ing. Markus Biermaier

- [Hantelscheiben Rechner](https://appshunter.io/ios/app/hantelscheiben-rechner/id6756926833)
- [nSuns 531 Powerlifting](https://appshunter.io/ios/app/nsuns-531-powerlifting/id6757189291)
- [PPL Weightlifting](https://appshunter.io/ios/app/ppl-weightlifting/id6757571517)
- [MMA Round Timer](https://appshunter.io/ios/app/mma-round-timer/id6757946803)

All apps by Ing. Markus Biermaier: https://appshunter.io/developer/1843098624

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-25.*